Bone is a composite material that contains impure hydroxyapatite, collagen and a variety of non-collagenous proteins, as well as embedded and adherent cells. Due to disease, a congenital defect or an accident, a person may lose or be missing part or all of one or more bones or regions of cartilage in his or her body, and/or have improper growth or formation of bone and/or cartilage.
That an organism is missing part of a bone or has a defect is not necessarily a permanent condition, and there are known means by which to address some of these conditions. For example, mammalian bone tissue is known to contain one or more proteinaceous materials that are active during growth and natural bone healing. These materials can induce a developmental cascade of cellular events that results in bone formation. Typically, the developmental cascade of bone formation involves chemotaxis of mesenchymal cells, proliferation of progenitor cells, differentiation of cartilage, vascular invasion, bone formation, remodeling and marrow differentiation. Thus, the control or use of this already existing system can be advantageous when seeking to regenerate or to repair bone.
Often times an allograft material can be used to aid in bone growth and repair of the bone defect. To enhance bone growth, the allograft can be seeded or hydrated with nucleated cells (e.g., white blood cells, red blood cells, progenitor cells, stem cells, etc.) often obtained from blood or bone marrow aspirates. It is desirable to have these nucleated cell types concentrated in the delivery liquid so they can easily be delivered to the allograft material.
Sometimes, it can be difficult to concentrate the cells in the fluid it is obtained from unless laboratory facilities are used. For example, when separating or removing cells from liquid, a filter is used. However, some filters do not easily let the cells through them and may require the use of a centrifuge. Further, because the centrifuge spins the liquid at high speeds, it can damage the nucleated cells causing them to be ineffective when they are added to the allograft material.
When using a centrifuge, installing the sample holding container assemblies in the centrifuge can only be done manually, making it difficult to automate a series of operations including preprocessing. Further, the speed of the centrifuge is the only parameter that can be controlled, which makes fine motor control of the device impossible. Still another problem is that an appropriate centrifugal force needs to be set according to liquid volumes and filter pore diameters, making the equipment difficult to handle.
It is therefore desirable to provide a filtration device and method, which can filter and concentrate cells from or in a liquid conveniently and with a simple construction.